Flu shot coverage in toddlers varied widely in 2005-06

Dec 18, 2006 (CIDRAP News) – Influenza vaccination coverage in children between 6 and 23 months old varied widely across the country in the 2005-06 flu season, the second season in which shots were recommended for that age-group, according to federal health officials.

Vaccination rates ranged all the way from less than 7% to more than 60% across six sampling areas, the Centers for Disease Control and Prevention (CDC) said in the Dec 15 Morbidity and Mortality Weekly Report.

The CDC gathered data from immunization information system (IIS) sentinel sites in Arizona, Michigan, Minnesota, Montana, Oregon, and Washington, DC. IISs are confidential electronic systems used primarily to maintain vaccination records. The sentinel sites consist of adjoining counties or census tracts in which data are collected on at least 10,000 children younger than 6 years old.

Vaccination coverage was estimated for children who were between 6 and 23 months during the entire period from September 2005 through March 2006.

Coverage with at least one dose ranged from 6.6% to 60.4% among the sentinel sites, the CDC reported. The rates for full vaccination (two or more doses) ranged from 2.3% to 43.4%. The report did not list which sites had which rates.

Compared with the 2004-05 flu season, vaccination coverage increased in four of the areas and decreased in two.

The uneven coverage probably reflected varying promotion and reporting efforts, according to the CDC. For example, healthcare workers in one area said anecdotal evidence and previous surveys suggested that "the low reported vaccination coverage likely reflects underreporting of influenza vaccination to the IIS rather than the actual coverage," the article says.

However, the report also says that previous National Immunization Survey (NIS) estimates of flu vaccination among children have been similar to IIS estimates. The NIS combines a telephone survey of households with a mail survey of vaccination providers.

NIS results for the 2005-06 flu season are not yet available. The NIS survey for 2004-05 indicated that 33.4% of 6- to 23-month-olds received at least one dose of flu vaccine, according to a CDC report released in October. That was double the rate for the 2003-04 season.

The CDC made its first full recommendation for vaccinating 6- to 23-month-olds before the start of the 2004-05 flu season. Previously the agency "encouraged" vaccination for children in that group.